As low-dimensional nano materials composed of carbon atoms, there are fullerene, carbon nanotube, graphene, graphite, or the like. That is, the low-dimensional nano materials may be classified into the fullerene having a 0-dimensional structure if the carbon atoms have a ball shape while having a hexagonal arrangement, the carbon nanotube if the carbon atoms are rolled one-dimensionally, the graphene if a layer consists of carbon atoms in two dimension, and the graphite if the carbon atoms are accumulated three-dimensionally.
In particular, the graphene is a material that has excellent conductivity as well as is very stable and excellent in electrical, mechanical, and chemical properties and may move electrons 100 times as fast as silicon and move a current about 100 times larger than copper, which was proved by an experiment since a method of separating graphene from graphite is discovered in 2004. Many studies have been conducted up to now.
Further, the graphene has high thermal conductivity (˜5000 Wm−1 K−1), excellent mobility of a charge carrier (200,000 cm2 V−1s−1), a large specific surface area (2,630 m2g−1), and excellent mechanical stability. Thanks to the excellent properties, the graphene has been attracting much attention since first discovery of 2004 and many studies for applying the graphene to various fields such as field effect transistor (FET), supercapacitor, hydrogen generation/storage, solar cell, photocatalyst, and biosensor have been intensively conducted.
To manufacture the graphene, various methods have been known. For example, as various methods, there are a method of delaminating an adhesive tape of an individual graphene layer from graphite, a method of chemically delaminating a graphene layer from graphite, and a chemical deposition method each of which provides approximately a pico gram amount of graphene. Further, some lithography and synthesis procedures have been developed to manufacture an ultra small quantity of graphene nanoribbon.
As other methods, a method of manufacturing a microscopic quantity of graphene nanoribbon by partially encapsulating carbon nanotube among polymers and longitudinally cutting the carbon nanotube by performing plasma etching and a method of manufacturing graphene nanoribbon by adding multi-walled carbon nanotube (MWNT) to a liquid ammonia solvent and causing delamination by interaction and reaction of the MWNT with lithium to non-selectively open the MWNT in a longitudinal direction have been known.
However, when manufacturing the graphene, the method has a fundamental problem in that it is difficult to obtain a material having a size fitting for a use purpose or a uniform size and make a structure of both ends or corners of 2D uniform, or change a material to be fitted for a purpose. In particular, the graphene heat treated by an activation treating process using potassium hydroxide has been reported that it has a high specific surface area (3100/g) but affects a 2D structure that is unique properties of the graphene (Carbon-Based Supercapacitors Produced by Activation of Graphene, Yanwu Zhu et al., Science 332, 1537 (2011)) and when the carbon nanotube is open in a longitudinal direction by using permanganate, oxygen of a graphene edge has to suffer from reduction processing with hydrazine but the graphene is harmful to a human body due to toxicity of the hydrazine, and has reduced electronic characteristics due to oxidized defects.
Further, to apply the graphene to various functional elements, a doping process capable of improving electrical characteristics such as face resistance of the graphene and charge mobility is essential but the foregoing methods have to add a separate doping process to a deposition device, or the like, and therefore require a long process time and consume much time and costs for the processing process.